Gas laser device

ABSTRACT

A gas laser device in which a laser medium gas is circulated in an airtight container and a laser beam is generated from the gas excited by an electric discharge, includes a main unit (10) including an air blower (13) for circulating the gas, heat exchangers (12a, 12b) for cooling the gas, and a discharging power supply (11). A laser beam emitter (20) includes a discharging unit (23) and resonator reflecting mirrors (21a, 21b). The main unit (10) and the laser beam emitter (20) are separate and spaced from each other. The main unit (10) and the laser beam emitter (20) are interconnected by a gas pipe assembly having a plurality of highly rigid steel pipes and flexible, expandable/contractable, airtight connector members (31a, 31b) connecting the steel pipes.

STATEMENT OF RELATED APPLICATIONS

The present invention is related in subject matter to U.S. Ser. No.177,660, filed Mar. 7, 1988.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a gas laser device for use inmachining, and more particularly, to a gas laser device having a mainunit including a power supply, and a laser beam emitter separate fromthe main unit.

2. Description of the Related Art

Gas laser devices are widely used for cutting and welding metal. Twotypical gas laser devices are shown in FIGS. 9 and 10.

FIG. 9 shows a high-speed axial-flow-type gas laser device whichincludes a laser beam, 61 resonator reflecting mirrors, 62a and 62b adischarge tube, 64a, 64b heat exchangers 64a and 64b for absorbing heatof the discharge gas and discharging the same to cool the gas, an airblower 65 for circulating a laser medium gas, and a DC high-voltagepower supply 66 for generating electric discharges in the dischargetube.

In this type of gas laser device, electric discharges are produced inthe discharge tube 63 to excite the laser medium gas which flows at ahigh speed in the tube for thereby causing laser excitation.

FIG. 10 shows an orthogonal-type gas laser device. Those parts which areidentical to those shown in FIG. 9 are denoted by identical referencenumerals, and will not be described in detail. Discharge electrodes 67aand 67b disposed in an opposing relation to each other.

In this type of gas laser device, electric discharges are generatedbetween the electrodes 67a and 67b to excite a laser medium gas flowingat a high speed between the electrodes for laser excitation.

In order to operate a gas laser device efficiently on a continued basis,the temperature of the gas in a discharging unit must be kept low. Bothof the above gas laser device types are equipped with a heat exchangerand an air blower, and a discharging power supply of a substantial size,and hence have a substantial weight and volume as a whole.

Systems for machining workpieces using the above laser devices include asystem in which the workpiece is moved and a system in which a laserbeam is scanned. In the system in which the workpiece is moved, amachining table is large in size, the machining speed is low, andthree-dimensional machining is especially difficult to achieve.Therefore, the system in which the laser beam is scanned and a system inwhich the workpiece is moved and the laser beam is scanned are mainlyrelied upon at present.

When the laser beam is scanned, however, the optical distance betweenthe laser device and the workpiece is varied, resulting in loweredmachining performance.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a gas laser devicewhich will solve the above problem and has a main unit including a powersupply, and a laser beam emitter separate from the main unit.

To solve the above problems, there is provided in accordance with thepresent invention a gas laser device in which a laser medium gas iscirculated in an airtight container and a laser beam is generated fromthe gas excited by an electric discharge.

A main unit includes an air blower for circulating the gas, a heatexchanger for cooling the gas, and a discharging power supply.

A laser beam emitter includes a discharging unit and resonatorreflecting mirrors and is separate from the main unit; and

A gas pipe assembly couples said main unit and said laser beam emitter,and includes a plurality of highly rigid steel pipes and flexible,expandable/contractable, airtight connector members connecting the steelpipes.

Since the laser beam emitter is separate from the main unit, the laserbeam emitter may be installed in the vicinity of a laser machining head.The laser beam is not required to traverse a long distance using mirrorsproviding a folded laser beam passage, and stable machining is madepossible.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first preferred embodiment of thepresent invention;

FIG. 2 is a schematic cross-sectional view of the embodiment of FIG. 1;

FIG. 3 is a perspective view of a second preferred embodiment of thepresent invention;

FIG. 4 is a perspective view of a third preferred embodiment of thepresent invention;

FIG. 5 is a schematic cross-sectional view of the embodiment of FIG. 4;

FIG. 6 is a schematic cross-sectional view of a fourth preferredembodiment of the present invention;

FIG. 7 is a perspective view of a fifth preferred embodiment of thepresent invention;

FIG. 8 is a cross-sectional view of a heat exchanger employed in theembodiment of FIG. 7;

FIG. 9 is a cross-sectional view of a conventional high-speed axial-flowtype gas laser device;

FIG. 10(a) is a sectional front elevational view of a conventionalorthogonal-type gas laser device; and

FIG. 10(b) is a sectional side elevational view of the conventionalorthogonal-type gas laser device of FIG. 10a.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will hereinafter be described inspecific detail with reference to the drawings.

Referring to FIGS. 1 and 2, a gas laser device includes a laser beam, amain unit 10 including a power supply 11, heat exchangers 12a and 12b,and an air blower 13. A laser beam emitter includes a discharging unit23 having discharging electrodes 24a and 24b and resonator reflectingmirrors, 21a and 21b and a gas pipe assembly 30 for supplying a lasermedium gas from the main unit 10 to the laser beam emitter 20 andreturning a high-temperature laser medium gas back to the main unit 10.The gas pipe assembly 30 has gas pipes 31a, 31b, 31c, 31d, 31e, and 31fof telescopic structure for enabling the gas pipe assembly 30 to beexpanded and contracted three-dimensionally.

FIG. 2 is a schematic cross-sectional view of FIG. 1. The gas pipes 31c,31d, 31e, 31f of telescopic structure are omitted from illustration inFIG. 2. Denoted in FIG. 2 at 1 is the laser beam the main unit 10 has apower supply 11, an air blower 13, and heat exchangers 12a and 12b. Thearrow in FIG. 2 indicates the direction of flow of the laser medium gas.

The laser beam emitter 20 has resonator reflecting mirrors 21a and 21bfor reflecting and resonating the laser beam and discharging electrodes33a, 33b for generating an electric discharge, and a discharging unit 23for exciting the laser medium gas.

The gas pipe assembly 30 has the gas pipes 31a and 31b of telescopicstructure which include packings 32 for preventing air from being mixedinto the laser medium gas. The laser beam emitter 20 is allowed to movelaterally in FIG. 2 by the gas pipes 31a and 31b of telescopicstructure. As described above, the gas pipes 31c, 31d, 31e and 31f oftelescopic structure, which are omitted from illustration in FIG. 2, actsimilarly to allow the laser beam emitter 20 to movethree-dimensionally.

FIG. 3 shows a second embodiment of the present invention. As with FIG.1, the reference numeral 10 represents a main unit, and 20 a laser beamemitter. In this embodiment, a gas pipe assembly 30 employs flexiblebellows 34a, 34b, and 34c as coupling pipes. The bellows are flexible,expandable and contractable for allowing the laser beam emitter 20 tomove three-dimensionally.

FIGS. 4 and 5 show a third embodiment of the present invention. In FIG.4, a laser beam emitter 20 is mounted on the distal end of a robot arm41 of a robot 40. A gas pipe assembly 30 is incorporated in the arm 41of the robot 40. Movement of the robot 40 causes the laser beam emitter20 to move three-dimensionally for machining a three-dimensionalworkpiece with a laser beam. While the gas pipe assembly 30 ispreferably combined with the arm 41 of the robot 40 in as theillustrated embodiment, the gas pipe assembly 30 may be installedoutside of and along the arm 41.

FIG. 5 is a schematic cross-sectional view of embodiment of FIG. 4. Inthis embodiment, the arm 41 serves as a passage for a laser medium gas,and arm joints are sealed from atmosphere. This arrangement eliminatesany special laser medium gas pipes, resulting in a reduced number ofparts. Denoted in FIG. 5 at 41a and 41b are rotary seal mechanisms, and42 a bellows.

FIG. 6 illustrates a fourth preferred embodiment. The fourth embodimentemploys a lateral excitation type structure for a laser beam emitter 20.Those parts which are identical to those of the first through thirdembodiments are denoted by identical reference numerals. A power supply11 is contained in a main unit 10 (not shown), and is shown forreference only. In the lateral excitation type structure, a dischargingdirection, a laser beam direction, and a laser medium gas flowingdirection are perpendicular to each other, making it possible to reducethe size of the laser beam emitter 20, which may advantageously bemounted on the distal end of a robot arm.

FIGS. 7 and 8 show a fifth preferred embodiment. In FIG. 7, a heatexchanger 50 is added to a gas pipe assembly 30 for cooling a lasermedium gas. Cooling water 51 is circulated by a pump or the like (notshown) through water pipes 52a and 52b for supplying the cooling water.

FIG. 8 shows the heat exchanger 50 in cross section. Cooling water 51enters a water passage 53 for passage of water. A heat exchanger core 54transmits heat from the laser medium gas to the cooling water, and gaspassage 55 passes the laser medium gas. While water is used as a coolantin the present embodiment, other coolants may be used. Where the gaspipe 20 is considerably long, the thermal resistance of the heatexchanger core may be reduced, and the gas may be cooled by air.

With the present invention, as described above, a main unit including apower supply and a heat exchanger, and a laser beam emitter are separatefrom each other and interconnected by a gas pipe assembly having aplurality of pipes which are coupled by flexible,expandable/contractable, and airtight members. Therefore, the laser beamemitter can easily be installed on a laser machining head, resulting ina simplified laser machining apparatus structure. Since the laser beamis not required to traverse a long distance using mirrors providing afolded laser beam passage, stable machining is made possible.

I claim:
 1. A gas laser device having a laser medium gas circulated inan airtight container and a laser beam generated from the gas excited byan electric discharge, comprising:a main unit including an air blowerfor circulating the gas and a discharging power supply; a laser beamemitter including a discharging unit and resonator reflecting mirrorsand being spaced from the main unit; and a telescopic gas pipe assemblycoupling said main unit and said laser beam emitter, said gas pipeassembly including a plurality of highly rigid steel pipes and aplurality of flexible, expandable/contractable, airtight connectormembers for interconnecting the steel pipes.
 2. A gas laser deviceaccording to claim 1, wherein said connector members are bellows.
 3. Agas laser device according to claim 1, further comprising a robot havingan arm, said laser beam emitter being mounted on a distal end of the armof the robot, and said gas pipe assembly being mounted on the arm of therobot.
 4. A gas laser device according to claim 1, further comprising arobot having an arm, said laser beam emitter being mounted on a distalend of the arm of the robot, and the arm of the robot comprises said gaspipe assembly.
 5. A gas laser device according to claim 1, wherein saidlaser beam emitter is a lateral excitation type laser beam emitter.
 6. Agas laser device according to claim 1, wherein said gas pipe assemblyincludes a heat exchanger disposed around the pipes of the gas pipeassembly and having a cooling medium.
 7. A gas laser device according toclaim 6, wherein said cooling medium is water.
 8. A gas laser deviceaccording to claim 7, wherein said heat exchanger comprises a waterpassage, a heat exchanger core within the water passage, and a gaspassage within the heat exchanger core.
 9. A gas laser device accordingto claim 8, wherein the communicating means comprises an interiorpassageway passing through the robot and robot arm, and rotary sealsprovided at movable portions of the robot and robot arms.
 10. A gaslaser device having a laser medium gas and a laser being generated fromthe gas excited by an electric discharge, comprising:a main unitincluding an air blower for circulating the gas and a discharging powersupply; a laser beam emitter including a discharging unit and resonatorreflecting mirrors and being spaced from the main unit; and a robothaving an arm, the laser beam emitter being mounted on a distal end ofthe robot arm, the robot and robot arm providing means for communicatingthe laser medium gas from the main unit to the laser beam emitter.